Sound translating device



1944- A. F. HORLACHER 2,355,298

SOUND TRANSLATING DEVICE Filed Jan. 27, 1941' IIIIIIIIIIIIIIIIII INVENTOR. ALBERT F .HORLACHER BY M ATTORNEYS.

Patented Aug. 8, 1944 SOUND TRAN SLATING DEVICE Albert F. Horlacher, Genoa, Iil., assignor to Antomatic Electric Laboratories, Inc., a corporation of Delaware Application January 27, 1941, Serial No. 376,095

7 Claims.

The present invention relates to sound translating devices and more particularly to sound translating devices adapted for use in both telephone transmitters and telephone receivers of the sound-powered type of the general character of that disclosed and claimed in U. S. Patent No. 2,100,500, Woodruif and Sengebusch, granted November 30, 1937.

A sound translating device of this character must be of compact and light-weight construction; yet it must have a fairly large diaphragm, a relatively strong magnetic field structure and a considerable winding in order to insure proper operation thereof. In order to satisfy these specifications, it has been necessary heretofore to design the component parts of the sound translating device so that they are arranged in nested or interfitting relation, as evidenced by the sound translating device disclosed in the Woodruf! and Sengebusch patent.

While sound translating devices of this char-- acter are entirely satisfactory in operation, they require nice design and assembly operations; and considerable design limitations are imposed'upon the component parts thereof due to the nesting or interiitting relation therebetween.

Accordingly, it is the principal object of the invention to provide an improved sound translating device of the type mentioned, which is of simple and economical construction and which is of compact and light-weight construction and arrangement.

Another object of the invention is to provide in a sound translating device an improved electromagnetic circuit, in which the principal field structure and the associated winding are arranged in noninterfitting relation, yet which is of extremely compact construction and arrangement.

The objects set forth above are attained in accordance with the present invention by providing a sound translating device comprising a support, a unitary field structure, including a permanent magnet and a field gap and secured to the support, a core element secured to the support, a winding spool carriedby the core element, and a winding carried by the winding spool, the field structure and the core element being secured to the same side of the support in spaced-apart relation, whereby the core element and the winding spool are arranged entirely exteriorly of the field structure. Also, the device comprises a movable armature adapted to couple the field structure and the core element, whereby the magnetic flux produced by the permanent magnet and traversing the field structure is coupled by way of the armature to the core element only when the armature is displaced from its normal position, a vibratory diaphragm mounted on the opposite side of the support, and means including a member projecting through an opening provided in the support for connecting the armature and the diaphragm. More particularly, the field structure includes a substantially U-shaped field element and a permanent magnet disposed between the legs of the field element to form two spaced-apart field gaps; while the armature includes two resilient arms carried by the opposite ends of the core element and respectively projecting into the two field gaps, whereby the magnetic flux produced by the permanent magnet and traversing the field gaps restrains the arms in balanced condition in the field gaps and is coupled by way of the arms to the core element only when the arms are displaced from their balanced condition in the field gaps.

The novel features believed to be characteristic of the invention are set forth with particularity in the appended claims. The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawing, in which Figure 1 is a plan view of a sound translating device embodying the present invention, illustrating the relative positions of the elements housed in the casing thereof when the cover is removed; and Fig. 2 is a transverse sectional view of the device shown in Fig. 1.

Referring now more particularly to the drawing, there is shown a sound translating device Ill which is adapted to be incorporated in either a telephone transmitter or a telephone receiver of the sound-powered type and which embodies the present invention. The device in comprises a casing including an annular supporting plate II and an inverted cup-shaped cover l2 suitably secured thereto. Preferably, the supporting plate ii is formed of a suitable nonmagnetic material, such asaluminum; while the cover I! is formed of a moldable plastic insulating material, such as Bakelite. Also, the device i0 comprises a principal field structure including a substantially U-shaped field element I4, a bar-like permanent magnet II and a pole piece it. One end of the permanent magnet II is positioned in a recess ll provided in the bottom of the U-shaped field element II; and the other end of the permanent magnet II is positioned in a recess i8 provided in the mid-section of the pole piece ll. Accordingly, the permanent magnet II is disposed between the legs of the U-shaped field element I4 and is retained in place by an arrangement comprising two spacing washers II and 20 and a screw 2|, the screw 2| extending through aligned openings provided in the legs of the U-shaped field element It, the spacing washers l9 and 20 and the permanent magnet II, and threaded in a tapped hole provided in the supporting plate II. It is noted that the pole piece ii is secured to the end of the permanent magnet I! in any suitable manner, whereby two field gaps are respectively formed between the opposite ends of the pole piece l6 and the respective legs of the U- shaped field element ll. Also, it is noted that the principal field structure as a whole is secured by the screw 2| to the top side of the supporting plate H on the left the center thereof. Preferably, the field element H and the pole piece I! are formed of Allegheny electric metal; the permanent magnet II is formed of Alnico; and the spacing washers l0 and 20 and the screw 2| are formed of nonmagnetic material, such as brass.

Further, the device ll comprises a core element 22 surrounding a stud 23 having a threaded end secured in a. tapped hole provided in the supporting plate It. The core element 22 carries a surrounding winding spool 24 which in turn carries a surrounding winding 2!. A composite armature including two resilient arms 28 and 21 is carried by the core element 22, the resilient arms 26 and 21 being respectively carried by the upper and lower ends of the core element 22. The resilient arms 26 and 21 are securely clamped to the opposite ends or the core element 22 by an arrangement comprising the stud 2i and a nut 28, the stud 23 passing through aligned openings respectively provided in the outer ends of the resilient arms 20 and 21. More particularly, the outer end of the resilient arm 28 is clamped between the upper end of the core element 22 and the nut 28; while the outer end of the resilient arm 21 is clamped between the low er end 01 the core element 22 and an integral boss 29 carried by the stud 22. The resilient arms 28 and 21 are arranged in vertical alignment and extend over the center of the supporting plate I I, whereby the inner end of the resilient arm 20 projects into the field gap disposed between the upper end oi. the pole piece II and the adjacent leg of the U-shaped field element II and the inner end of the resilient arm 21 projects into the field gap disposed between the lower end of the pole piece I8 and the adjacent leg 01' the U- shaped field element H. The inner ends of the resilient arms 28 and 21 are positively positioned with respect to the associated field gaps by an arrangement comprising two pairs 01' bosses I0 and II respectively carried by the upper and lower ends of the winding spool 24. More particularly, the extreme outer end oi the resilient arm 26 is bent downwardly between the pair 01 bosses 20 carried by the upper end of the winding spool 24; and the extreme outer end of the resilient arm 21 is bent upwardly between the pair of bosses ll carried by the lower end of the winding spool 24. Preferably, the core element 22 and the resilient arms 28 and 21 are iormed of Allegheny electric metal; the winding spool is formed of a moldable plastic insulating material, such as Bakelite and the stud 22 and the nut 22 are formed of nonmagnetic material, such as brass.

Accordingly, the stud 2!, the core element 22, the winding spool 24 and the winding 28 carried thereby are disposed upon the top of the supporting plate II and are positioned on the opposite side of the center thereof with respect to the principal field structure including the field element ll, the permanent magnet II and the pole piece I.

Further, the device ll comprises a resilient annular diaphragm 32 mounted on the bottom oi the supporting plate It by an arrangement comprising an annular clamping ring 38 and a plurality 0! screws 34, the inner ends of the screws I4 being threaded into tapped holes provided in the periphery oi the supporting plate II. The composite armature, including the resilient arms 28 and 21, is operatively connected to the diaphragm 22 by an arrangement comprising an operating member 25 projecting through a centrally disposed opening 38 formed in the supporting plate II. More particularly, the operating member 36 projects through aligned openings respectively provided in the resilient arms 2 and 21 and in the diaphragm 22, in addition to the centrally disposed opening 26 provided in the supporting plate I I. The lower end oi. the operating member I! is secured to the diaphragm I2 by an arrangement comprising two clamping nuts 21; the upper end of the operating member 25 is secured to the resilient arm 2! by an arrangement comprising two clamping nuts 38; while the intermediate section of the operating member II is secured to the resilient arm 21 by an arrangement comprising two clamping nuts 3!. Preterably, the diaphragm 12 is formed of a suitable resilient material; the clamping ring 22 is formed 01' a suitable nonmagnetic material, such as aluminum; and the operating member 35 is iormed 01' a suitable nonmagnetic material, such as brass.

When the device I0 is utilized as a telephone transmitter and the diaphragm 32 is at rest, a normal magnetic fiux traverses the principal field structure excluding the core element 22. This magnetic fiux traverses a magnetic circuit extending from the north pole of the permanent magnet II by way of the upper end of the pole piece I, the associated field gap and the upper leg of the field element It to the south pole oi the permanent magnet I5; and from the north pole or the permanent magnet I! by way 0! the lower end of the pole piece It, the associated field gap and the lower leg of the field element II to the south pole of the permanent magnet ii. The magnetic fiux traversing the field gaps respectively associated with the upper and lower ends of the pole piece I! acts upon the inner ends of the respective resilient arms 26 and 21, thereby to restrain the inner ends oi the resilient arm 2| and 21 in balanced condition in the respective associated field gaps.

When the diaphragm 32 is vibrated the composite armature, including the resilient arms 22 and 21, couple the principal field structure to the core element 22. More particularly, when the diaphragm I2 is moved upwardly the operating member 3| flexes both of the resilient arms 28 and 21 upwardly, whereupon a magnetic circult is completed between the rincipal magnetic structure and the core element 22. The masnetic flux traversing this magnetic circuit extends from the north pole of the permanent magnet ID by way of the lower end of the pole piece ii, the associated field gap, the resilient arm 21, the core element 22, the resilient arm 26, the associated field gap and the upper leg 0! the field element I4 to the south pole of the permanent magnet I5. On the other hand, when the diaphragm 32 is moved downwardly the operatin member 35 flexes both of the resilient arms 26 and 21 downwardly, whereupon a magnetic circuit is completed between the principal magnetic structure and the core element 22. The magnetic flux traversing this magnetic circuit extends from the north pole of the permanent magnet I5 by way of the upper end of the pole piece I6, the associated field gap, the resilient arm 26, the core element 22, the resilient arm 21, the associated field gap and the lower leg of the field element I4 to the south pole of the permanent magnet I5. Accordingly, the magnetic fiux traverses the core element 22 in opposite directions in accordance with the corresponding movements of the diaphragm 32 and, accordingly, in accordance with the sound waves acting upon the diaphragm 32, whereupon a corresponding signal voltage is generated in the winding 25 coupled to the core element 22.

When the device I is utilized as a telephone receiver and the winding 25 is deenergized the normal magnetic flux traverses the principal field I structure, excluding the core element 22, in the manner previously explained, thereby to restrain the inner ends of the resilient arms 26 and 21 in balanced condition in the respective associated field gaps, as previously noted.

When the winding 25 is energized the composite armature, including the resilient arms 26 and 21, couple the core element 22 to the principal field structure. More particularly, when the winding 25 is energized with current of one polarity a magnetic fiux traverses the core element 22, rendering the inner ends of the resilient arms 26 and 21, respectively, north and south poles; whereupon the inner end of the resilient arm 26 is repelled in the associated field gap by the upper end of the pole piece I6 connected to the associated north pole of the permanent magnet I and the inner end of the resilient arm 21 is attracted in the associated field gap by the lower end of the pole piece I6 connected to the associated north pole of the permanent magnet I6. Accordingly, the composite armature, including the resilient arms 26 and 21, is moved upwardly, thereby to cause the operating member 35 to fiex the daiphragm 32 upwardly. On the other hand. when the winding 25 is energized with current of the opposite polarity a magnetic flux traverses the core element 22, rendering the inner ends of the resilient arms 21 and 26, respectively, north and south poles; whereupon the inner end of the resilient arm 21 is repelled in the associated field gap by the lower end of the pole piece I6 connected to the associated north pole of the permanent magnet I5 and the inner end or the resilient arm 26 is attracted in the associated field gap by the upper end of the'pole piece I6 connected to the associated north pole of the permanent magnet I5. Accordingly, the composite armature, including the resilient arms 26 and 21, is moved downwardly, thereby to cause the operating member 35 to flex the diaphragm 32 downwardly. Accordingly, the diaphragm 32 is vibrated in accordance with a signal current traversing the winding 25, whereupon a corresponding sound is produced.

The arrangement of the principal field structure, including the field element II, the permanent magnet I5 and the pole piece I6 on one side of the center of the supporting plate II and the core element 22, the winding spool 24 carried thereby, and the winding 26 carried by the winding spool 24 on the opposite side of the center on the supporting plate II, is very advantageous in view of the fact that it materially contributes toward compactness and symmetry or balance of the device III. Also, this arrangement oi! the winding 25 entirely exteriorly of the principal field structure permits of considerable flexibility of design of the winding 25 relative to the dimensions thereof and consequently the electromagnetic character of the winding 25.

While there has been described what is at present considered to be the preferred embodiment of the invention, it will be understood that var,- ious modifications may be made therein, and it is intended to cover in the appended claims all such modifications as fall within the true spirit and scope of the invention.

What is claimed is:

1. A magnetic unit for a sound translating device comprising a support, a unitary field structure including a permanent magnet and carried by said support, a core element carried by said support, a winding carried by said core element, said core element and said winding being ar ranged entirely exteriorly of said field structure, and a movable armature carried by said core element and arranged entirely exteriorly of said winding and cooperating with said field structure, said armature having a normal position with respect to said field structure and being so constructed and arranged that the magnetic fiux produced by said permanent magnet and traversing said field structure is coupled by way of said armature to said core element only when said armature is displaced from its normal position with respect to said field structure.

2. A magnetic unit for a sound translating device comprising a support, a unitary field structure including a permanent magnet and carried by said support, a core element carried by said support, a winding spool carried by said core, a winding carried by said winding spool, said core element and said winding spool being arranged entirely exteriorly 01 said field structure, a resilient armature carried by said core element and arranged entirely exteriorly of said winding spool and cooperating with said field structure, said armature having a normal position with respect to said field structure and being so constructed and arranged that the magnetic fiux produced by said permanent magnet and traversing said field structure is coupled by way of said armature to said core element only when said armature is displaced from its normal position with respect to said field structure, and means carried by said winding spool for positively positioning said armature with respect to said field structure.

3. A magnetic unit for a sound translating device comprising a support, a unitary field structure carried by said support, said field structure including a permanent magnet and a field gap, a core element carried by said support, a winding carried by said core element, said core element and said winding being arranged entirely exteriorly of said field structure, and a resilient armature carried by said coreelement and arranged entirely exteriorly of said winding and projecting into said field gap, said armature having a normal position in said field gap and being so constructed and arranged that the magnetic flux produced by said permanent magnet and traversing said field gap is coupled by way of said armature to said core element only when said armature is displaced from its normal position in said field gap.

a A magnetic unit for a sound translating device comprising a, support, a unitary field structure including a permanent magnet and two spaced-apart field gaps and carried by said support, a core element carried by said support, a winding carried by said core element, said core element and said winding being arranged entirely exteriorly oi said field structure, and an armature including two resilient arms carried by the opposite ends of said core element and respectively projecting into said two field gaps, said a ms having normal positions in said field gaps and being so constructed and arranged that the magnetic fiux produced by said permanent magnet and traversing said field gaps is coupled by way oi said arms to said core element only when said arms are displaced from their normal positions in said field gaps.

5. A magnetic unit for a sound translating device comprising a support, a unitary field structure carried by said support, said field structure including a substantially U-shaped field element a permanent magnet disposed between the of said field element to form two spacedapart field gaps, a core element carried by said support, a winding carried by said core element, said core element and said winding being arranged entirely exteriorly of said field structure, and an armature including two resilient arms carried by the opposite ends oi said core element and respectively projecting into said two field gaps, said arms having normal positions in said field gaps and being so constructed and arranged that the magnetic flux produced by said permanent magnet and traversing said field gaps is coupled by way of said arms to said core element only when said arms are displaced from their normal positions in said field gaps.

6. A magnetic unit for a sound translating device including an annular supporting plate, a unitary field structure secured to the top of said supporting plate on one side of the center thereof, said field structure including a substantially U-shaped field element and a permanent magnet disposed between the legs of said field element to form two spaced-apart field gaps, a core element secured to the top of said supporting plate on the opposite side of the center thereof, a.winding carried by said core element, and an armature including two resilient arms carried by the opposite ends of said core element and extending over the center of the top of said supporting plate and respectively projecting into said two field gaps, said arms having normal positions in said field gaps and being so constructed and arranged that the magnetic fiux produced by said permanent magnet and traversing said field gaps is coupled by way of said arms to said core element only when said arms are displaced from their normal positions in said field ga'ps.

7. A magnetic unit for a sound translating device comprising a support, a unitary field structure including a permanent magnet and a field gap and mounted on said support, a core element mounted on said support and extending upwardly therefrom at; a place removed from said field structure, a winding surrounding said core element, and a resilient armature mounted on the end of said core outside of said winding and extending transversely to said core into said gap.

ALBERT F. HORLACHER. 

